Density functional potential-energy hypersurface and reactivity indices in the isomerization of X₃H⁺ (X = O, S, Se, Te)

Abstract

Potential-energy hypersurfaces of protonated O₃, S₃, Se₃ and Te₃ systems have been investigated using the gradient-corrected density functional approximation. Both the open (C_2v) and cyclic (D_3h) X₃ structures have been considered in the protonation process. Results show that the relative stability of the cyclic form with respect to the trans-open one increases on going from O₃ to Se₃ and reverses for Te₃. The calculated density functional potential-energy surfaces are consistent with those (for ozone and thiozone) obtained at the ab initio correlated level of theory. The order of stability and reactivity indices has been rationalized on the basis of orbital hardness values along the reaction paths.